Certain things become Known in the software world (and elsewhere) and are propagated long after they become false. I just learned about a new one.
I've always warned people about deploying WAR files that Tomcat had a certain non-intuitive behavior. If the UnpackWars option was true (which it is by default) and you deploy by dropping a WAR file into the TOMCAT_HOME/webapps directory, Tomcat would unpack the WAR file and deploy the unpacked WAR. If you updated/replaced the WAR file, however, Tomcat did not update the unpacked WAR, which meant that the only way to get changes to a WAR file to "take" was to delete the unpacked WAR directory.
According to some JavaDocs I just read, that behavior is no longer true as of Tomcat version 8.0.2. Supposedly for that and all later releases, changing the WAR file will now automatically change the unpacked WAR.
It's still safe to delete the exploded WAR directory before updating a WAR file, but should no longer be essential.
When it comes to destroying a civilization, gas chambers cannot hold a candle to echo chambers.